The Collaborative International Dictionary of English v.0.48:

Inaccessible \In`ac*cess"i*ble\, a. [L. inaccessibilis: cf. F.
   inaccessible. See In- not, and Accessible.]
   Not accessible; not to be reached, obtained, or approached;
   as, an inaccessible rock, fortress, document, prince, etc. --
   In`ac*cess"i*ble*ness, n. -- In`ac*cess"i*bly, adv.
   [1913 Webster]

WordNet (r) 3.0 (2006):

inaccessible
    adj 1: capable of being reached only with great difficulty or
           not at all [syn: inaccessible, unaccessible] [ant:
           accessible]
    2: not capable of being obtained; "a rare work, today almost
       inaccessible"; "timber is virtually unobtainable in the
       islands"; "untouchable resources buried deep within the
       earth" [syn: inaccessible, unobtainable, unprocurable,
       untouchable]

Moby Thesaurus II by Grady Ward, 1.0:

71 Moby Thesaurus words for "inaccessible":
   Olympian, aloof, antipodean, back of beyond, backward, bashful,
   beyond reach, blank, chilled, chilly, closed forever to, closed to,
   cold, constrained, cool, detached, discreet, distant, exclusive,
   expressionless, far, far-off, faraway, forbidding, frigid, frosty,
   godforsaken, guarded, hyperborean, icy, impassable, impassive,
   impenetrable, impersonal, impervious, introverted, lost to, modest,
   offish, out of reach, out-of-the-way, remote, removed, repressed,
   reserved, restrained, reticent, retiring, seclusive, shrinking,
   standoff, standoffish, subdued, suppressed, un-come-at-able,
   unapproachable, unattainable, unavailable, uncongenial,
   undemonstrative, undiscoverable, unexpansive, ungenial,
   ungetatable, ungettable, unobtainable, unprocurable, unreachable,
   unsecurable, untouchable, withdrawn